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3.07 The sine rule

Worksheet
Sine rule
1

For each of the given triangles, determine if there is enough information to find all the remaining sides and angles in the triangle using only the sine rule:

a

Three sides are known:

b

Two of the angles and the side included between them are known:

c

Two of the angles and a side not included between them are known:

d

Two of the sides and an angle included between them are known:

2

Solve the following equations for x, given that all equations relate to acute-angled triangles. Round your answers to two decimal places.

a

\dfrac{x}{\sin 78 \degree} = \dfrac{50}{\sin 43 \degree}

b

\dfrac{11}{\sin 66 \degree} = \dfrac{x}{\sin 34 \degree}

c

\dfrac{\sin 78 \degree}{20} = \dfrac{\sin x}{13}

d

\dfrac{5}{\sin x} = \dfrac{7}{\sin 70 \degree}

e

\dfrac{22}{\sin x} = \dfrac{31}{\sin 66 \degree}

3

For each of the following triangles, write an equation relating the sides and angles using the sine rule:

a
b
Unknown sides
4

For each of the following triangles:

i

Find the value of a using the sine rule. Round your answer to two decimal places.

ii

Use another trigonometric ratio and the fact that the triangle is right-angled to calculate and confirm the value of a. Round your answer to two decimal places.

a
b
5

For each of the following triangles, find the side length a using the sine rule. Round your answers to two decimal places.

a
b
c
d
e
6

For each of the following triangles, find the length of side x, correct to one decimal place:

a
b
7

Consider the following triangle:

a

Find the length of side HK to two decimal places.

b

Find the length of side KJ to two decimal places.

8

Consider the triangle ABC, where BC = 37.8 \text{ m} , \angle BAC = 57 \degree and \angle ACB = 42 \degree.

Calculate the length of side AB, correct to two decimal places.

9

Consider the triangle PQR, where QR = 4.79 \text{ mm}, \angle QPR = 33 \degree and \angle PRQ = 124 \degree.

Calculate the length of side PQ, correct to two decimal places.

10

Consider the triangle ABC with \angle C = 72.53 \degree and \angle B = 31.69 \degree, and one side length \\ a = 5.816\text{ m}.

a

Find \angle A. Round your answer to two decimal places.

b

Find the length of side b. Round your answer to three decimal places.

c

Find the length of side c. Round your answer to three decimal places.

Unknown angles
11

Consider the given triangle:

a

Write out the sine rule to find h.

b

Find the value of h to two decimal places.

12

Consider the triangle MNP, where NP = 100 \text{ m} , MN = 204 \text{ m} and \angle NPM = 58 \degree.

Calculate the size of the acute angle \angle NMP, correct to the nearest minute.

13

For each of the following acute angled triangles, calculate the size of angle B to the nearest degree:

a

\triangle ABC where \angle A = 57 \degree side a = 156 \text{ cm} and side b = 179 \text{ cm}

b

\triangle ABC where \angle A = 48 \degree side a = 2.7 \text{ cm} and side b = 1.9 \text{ cm}

14

For each of the following diagrams, find the size of the angle x. Round your answers to one decimal place.

a
b
c
d
e
f
g
h
i
j
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Outcomes

MS2-12-3

interprets the results of measurements and calculations and makes judgements about their reasonableness, including the degree of accuracy and the conversion of units where appropriate

MS2-12-4

analyses two-dimensional and three-dimensional models to solve practical problems

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